What does longest mean?
The longest means greater in length or duration than anything else being considered. It is the superlative form of "long" and can describe a physical measurement, such as the longest river, road, or animal, as well as a span of time, as in "the longest conversation." The word may also function adverbially, particularly in comparisons involving duration: "She stayed longer than the others, but he stayed longest." Its meaning can occasionally be extended beyond measurements to mean "the greatest amount or degree," although that use is normally expressed more clearly with a noun such as "amount." Longest is especially common in superlative constructions such as "the longest-running process" and "the longest stretch of road."
Having the greatest length or lasting for the greatest amount of time.
"The museum occupies the longest building on the street."
This is the superlative form of the adjective "long."
For the greatest length of time.
"Of all the competitors, she ran longest."
This use is especially common in comparisons involving duration rather than physical distance.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does longest come from?
The word is formed by adding the superlative suffix -est to long. Long comes from Old English lang, a Germanic word meaning "long" or "long-lasting," with cognates including German lang and Dutch lang. Related English forms such as length and lengthen developed from the same Germanic base, while elongate and longitude were borrowed from Latin through the Latin root longus.
Related word forms
How longest is actually used
The word is the superlative of "long." In the sense "for the greatest amount of time," it may be used adverbially, as in "The exhibition runs longest in London." The phrase "at the longest" gives an upper limit rather than identifying a superlative example.